“The Kardashians, like Angela and my other clients are very protective of our marks, I think for us this is going to be a clear case win, because it’s actually her name, it’s not a poaching. I would hope that this is just a junior lawyer’s error, who’s just responding to everything and not really looking at who it’s from or why it was filed. There’s a softer side of this where Angela has to have a conversation with her family. But until I hear otherwise, I’m just going to proceed as I normally would with a lawsuit. I have 40 days to respond,” Mosley tells PEOPLE of the suit.

According to the documents previously obtained by PEOPLE, the sisters’ companies claim they’ll “suffer damage including irreparable injury to their reputation and goodwill” if Chyna takes the Kardashian name. The documents also say that Rob Kardashian‘s fiancée is “deliberately seeking to profit from the goodwill and popularity” by changing her name. (AngelaKardashian.com appears to have been registered in March by a woman in Georgia.)

But although the Kardashians are legally opposing her request, Mosley hopes that “it’s just a big misunderstanding.”

“I have to respond to the notice of opposition, so the way this works is we filed the mark, it was initially unopposed, it was published and then the representatives of the sisters’ companies filed an opposition to Angela owning her name. Sure, it’s not her legal name now, but it is certainly her stage name — her next stage name and her legal name once the wedding is done. In the complaint they are not short or shy as to how they feel about Angela using the trademark. I’m hoping that it’s just a big misunderstanding but I’m just proceeding as if it’s not and am going to do the best work I can for my client,” Mosley says.

Although this is the first trademark that Mosley has had opposed in the history of his filings for Chyna, he says that he is going to “zealously represent” her in the case.

“I filed this trademark with the utmost confidence that it would not be opposed at all. I did not foresee this, but in retrospect maybe I could have, all things considered,” Mosley says, and adds, “I’m going to zealously represent my client in a trademark we legally filed and a name that we feel like we own and need to protect.”

In April, Chyna got engaged to fiancé Rob and welcomed the couple’s first child together — Dream Renée Kardashian — in November. Although no plans for a wedding have been set, a source told PEOPLE that the couple are “getting along great and enjoying parenting together.”

“Everything has been fantastic between her and the family to the best of my knowledge, so this is a shock. Thus, I’m under the belief that it’s a misunderstanding. I don’t know how this plays out any other way,” says Mosley, who adds, “There’s a whole process that went on like anyone else does. So again, I’m hoping this just goes away once they see what it is. Angela, Rob and Dream are doing amazing, wonderful and things couldn’t be better.”